diff --git a/src/tt.cpp b/src/tt.cpp
index 8918e515..20ac1608 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -55,18 +55,18 @@ void TranspositionTable::set_size(size_t mbSize) {
 
   size_t newSize = 1024;
 
-  // Transposition table consists of clusters and
-  // each cluster consists of ClusterSize number of TTEntries.
-  // Each non-empty entry contains information of exactly one position.
-  // newSize is the number of clusters we are going to allocate.
-  while ((2 * newSize) * sizeof(TTCluster) <= (mbSize << 20))
+  // Transposition table consists of clusters and each cluster consists
+  // of ClusterSize number of TTEntries. Each non-empty entry contains
+  // information of exactly one position and newSize is the number of
+  // clusters we are going to allocate.
+  while (2ULL * newSize * sizeof(TTCluster) <= (mbSize << 20))
       newSize *= 2;
 
   if (newSize != size)
   {
       size = newSize;
       delete [] entries;
-      entries = new TTCluster[size];
+      entries = new (std::nothrow) TTCluster[size];
       if (!entries)
       {
           std::cerr << "Failed to allocate " << mbSize
diff --git a/src/tt.h b/src/tt.h
index 94ee78e7..c37b9d3f 100644
--- a/src/tt.h
+++ b/src/tt.h
@@ -46,7 +46,7 @@ class SimpleHash {
 public:
   SimpleHash() {
 
-    entries = new Entry[HashSize];
+    entries = new (std::nothrow) Entry[HashSize];
     if (!entries)
     {
         std::cerr << "Failed to allocate " << HashSize * sizeof(Entry)